Generally, a passenger seat airbag device for a passenger motor vehicle adopts a structure in which an inflator that generates expansion gas and an airbag that expands and deploys due to the gas are housed inside an instrument panel. During a collision of a vehicle, the inflator operates to expand the airbag, and the airbag deploys toward the inside of the vehicle to restrain a forward movement of an occupant.
In recent years, safety is increasingly being required in various collision modes including, in addition to a head-on collision in which a vehicle collides head-on with an obstacle (an oncoming vehicle or the like), a case where an obstacle collides with a part of a vehicle (an offset collision) and a case where a part of a vehicle collides with an obstacle from an oblique direction (skewed from the longitudinal direction).
FIG. 1 is a plan view which shows a structure of a conventional vehicle (a left-hand drive vehicle) including airbag devices for a driver's seat and a passenger seat and which shows a situation where the vehicle is approaching, at an angle of 0 degrees, an object (an obstacle) at a position deviated from directly in front of the vehicle. A driver's seat airbag 16 is housed inside a steering wheel 14 in front of a driver 10 and is configured to deploy toward the driver when a collision occurs. A passenger seat airbag 18 is housed inside an instrument panel in front of an occupant 12 of the passenger seat and is configured to deploy toward the occupant when a collision occurs. The airbags 14 and 18 are configured to expand due to expansion gas supplied from an inflator (not shown) which is operated by a signal of a collision sensor.
FIG. 2 is a plan view which shows a structure of a conventional vehicle mounted with airbag devices for a driver's seat and a passenger seat and which shows a situation where the vehicle is approaching, at a prescribed angle θ, an object (an obstacle) at a position deviated from directly in front. FIG. 3 shows a situation where a vehicle body rotates after colliding with the object (an obstacle) from the state shown in FIG. 2. In a situation such as that shown in FIG. 3, there is a risk that the occupant 12 of the passenger seat may slide across the side of passenger seat airbag 18 and collide with a center console between the driver's seat and the passenger seat. In this case, in addition to an injury caused by a direct collision with the center console, the occupant 12 may suffer head injury due to a rotation of the head. A brain damage index thereof is referred to as BRIC (Brain Rotational Injury Criteria).